The only vehicles that show no vacuum at idle are diesels, because they have no throttle plates. It will vary on your altitude, but -18 <--> -23 sounds healthy.

It's likely you tapped a line that has a check valve only allowing pressure, no vac OR you have a serious vac leak OR your gauge is busted.


EDIT: Sorry missed your post identifying a broken gauge. G'luck on the replacement!

 

Hello

So if I am showing a vac of -10 or -12 is that ok I checked it on my Cobb app?
I am running the beta stage 2 map for 2011 gsr and this is the vac I get don't know stock since the app is also my digital boost guage via. The tantrix cable.





Part list
k&n panel, Cobb turbo inlet tube, password jdm uicp, and invidia exh single out.

 

my thoughts are you have vac leak.
If you had cams, crazy cam timing, or crazy density-altitude differences than "norm" maybe it would be okay, but sounds like a leak. or crazy check valve issue.

Try connecting a gauge to a different location that is direct to the intake manifold and make sure there's no check valve/pill/etc in the way.

 

Ok well its the cobb app so only 1 place to plug it into.lol
But I called cobb they said the app reads it diffrent so a -9 to -10 is like -19 or -20.
Thanks for the reply.

 

COBB reads in PSI not in mmHG like a boost gauge usually does...

 

Had problems with an AEM guage where the 12v I tapped into did not calibrate correctly and it would not read vacuum. If it's a stepper motor based guage, it needs a second to calibrate before engine cranks. Wired to a stable 12v and the problem was gone, reads the correct 17-21 inches now.

Any way to talk you out of an MBC?

 

-20 here on a defi racer

 

Same goes for me. I am also using a defi racer.

 

so reading in psi is 9 to 10 ? im looking at buying a 08 gsr and that what the gauge is saying

 

good to know

 

0? WTF! Mine reads -18 Normally , might fluctuate -16 to -20 depending on weather/temp. But I would say -18 at idle is normal for me AEM Digital Boost Gauge.

 

what power source are you guys tapping your AEM digital gauges up to?

 

I had this issue aswell. Sometimes it pulls -20 but most times it resets to 0. Boooo analog

 

Piggyback fuse setup off of third up far right ( unless that was my wideband ) then one right below it.

 

My Cobb Ap reads -8 or -9. I guess I have a vacuum leak somewhere.